Allegedly disaffected of the national unification dynasty by having lost his father to battle against it, Marubashi orchestrated, along with a fellow martial arts adept named Yui Shosetsu, a daring plot betrayed only by illness. When shogun Tokugawa Iemitsu died in 1651, leaving power to a 10-year-old heir, the conspirators meant to set fire to Edo (Tokyo) and seize Edo Castle as well as other cities.

But Marubashi came down with a very ill-timed fever and in delirium raved treasonable plot details that got passed along to Tokugawa authorities. The so-called Keian Uprising never made it into execution.

Yui managed to commit seppuku before capture, but Murabashi and a number of the other rebels paid the ultimate price. So too did family members of the rebels.

Marubashi’s is reputed to be the first execution to take place at the Suzugamori execution grounds. The little quarter-acre patch maintained this grim role for the ensuing 220 years, during which time an estimated 100,000 people were put to death there.